Working machines are known in which it is possible to change a working tool to a working arm of the working machine. These kinds of changeable working tools may also be called as implements. Such implements may be coupled to the working arm e.g. by using an implement attachment. The working arm usually comprises two or more axes or other bar-like members (e.g. pins) which can be positioned through holes of two side walls of the implement attachment. One problem with such arrangements is that the holes in the implement attachment are fixed and only fit to working arms for which they have been designed. In other words, such implement attachments fit only such working arms in which the mutual distance between the axes correspond with the mutual distance between the holes in the implement attachment.
Some implement attachments are known in which an adapter may be put into the holes of the two side walls of implement adapter. The adapter comprises an eccentric hole for receiving the axis, wherein the distance between the acentric holes of the adapters may be slightly varied by rotating the adapters in the holes of the implement attachment. For example, the patent U.S. Pat. No. 7,204,656 discloses such arrangement for implement attachments. The arrangement comprises two or more adapters having acentric hole for receiving the axes of the working arm and threaded holes positioned in the circularly near an edge of a base element of the adapter. These threaded holes are for receiving tips of bolts for fixing the adapters to the walls of the implement attachment. Similar holes need also be formed to the walls of the implement attachment so that the bolts can be put through the holes of the walls of the implement attachment and screwed to the threaded holes of the adapter. Such a construction needs accurate machining (i.e. location of the holes in the walls of the of the implement attachment and the threaded holes of the adapters need to be accurately aligned). Furthermore, a relatively large number of bolts are need for fixing and thus there need to be a relatively large number of threaded holes in the adapters and holes in the walls of the implement attachment. Therefore, if the same implement attachment should be fixed to a different working arm in which the distance between the axes is different, at least one pair of the adapters need to be rotated into another position. This requires a lot of unscrewing and screwing work due to the high number of bolts.
WO03069077A1 discloses a connector assembly for attaching an implement to a prime mover having spaced connecting pins, the connector assembly including a pair of spaced plates, each of the plates carrying a first receiver to receive a first of the connecting pins and a second receiver adapted to receive the second of the connecting pins, wherein at least one of the first and second receivers is an adjustable receiver rotatable about an axis and having a transverse bore spaced radially from the axis and rotatable relative thereto, whereby rotation of the adaptable receiver about the axis changes the relative spacing.
The rotatable receiver may be positioned so that the distance between the connecting pins corresponds with the implement. Rotation of the rotatable receiver may be prevented by putting one or more lock pins into a receiver. Axial movement of the rotatable receiver may be prevented by providing a chamfered end at the end of the pin which may receive a lock ring and putting a washer between the lock ring and a side plate of the connector assembly.
This kind of construction has several drawbacks. For example, it may be difficult to remove the lock ring when the distance between the pins need to be changed. It may also be difficult to put the lock ring back when the receivers need to be secured in their place. Moreover, distance between the side plates of the connector assembly is not adjustable, wherein the connector assembly can only be used with implements in which the distance is appropriate.